3-D Macromolecule

[Side 1]

Primary Citation
Crystal structure of LexA: a conformational switch for regulation of self-cleavage.

Authors: Luo Y, Pfuetzner RA, Mosimann S, Paetzel M, Frey EA, Cherney M, Kim B, Little JW, Strynadka NC.

Journal: (2001) Cell(Cambridge,Mass.) 106: 585-594

PubMed: 11551506

PubMed Abstract:

LexA repressor undergoes a self-cleavage reaction. In vivo, this reaction requires an activated form of RecA, but it occurs spontaneously in vitro at high pH. Accordingly, LexA must both allow self-cleavage and yet prevent this reaction in the absence of... [ Read More & Search PubMed Abstracts ]

LexA repressor undergoes a self-cleavage reaction. In vivo, this reaction requires an activated form of RecA, but it occurs spontaneously in vitro at high pH. Accordingly, LexA must both allow self-cleavage and yet prevent this reaction in the absence of a stimulus. We have solved the crystal structures of several mutant forms of LexA. Strikingly, two distinct conformations are observed, one compatible with cleavage, and the other in which the cleavage site is approximately 20 A from the catalytic center. Our analysis provides insight into the structural and energetic features that modulate the interconversion between these two forms and hence the rate of the self-cleavage reaction. We suggest RecA activates the self-cleavage of LexA and related proteins through selective stabilization of the cleavable conformation.

Related Structures:
Primary Citation of: 1JHC 1JHE 1JHF 1JHH Also Cited By: 1Z0L

Organizational Affiliation:
Department of Biochemistry and Molecular Biology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, British Columbia, V6T 1Z3, Canada.

[Side 2]

Molecular Description

Classification : Hydrolase
Structure Weight : 29848.40
Molecule : LEXA REPRESSOR
Polymer : 1
Type : Polypeptide (L)
Length : 135 residues
Chains : A, B
EC Number : 3.4.21.88
Fragment : C-Terminus, Residues 68-202
Mutation : L89P, Q92W, E152A, K156A


Source

Polymer : 1
Scientific name : Escherichia coli
Expression System : Escherichia coli

[Side 3]

Experimental Details

Method: X-RAY DIFFRACTION
Experimental Data: [ EDS ]

Resolution[Å]:	2.50
R-Value:	0.220 (work)
R-Free:	0.284
Space Group:	C 2

Unit Cell:
	Length [Å]	Angles [°]
	a = 124.70	α = 90.00
	b = 43.70	β = 109.50
	c = 49.50	γ = 90.00

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Related PDB Enteries

Id	Details
1JHC	LEXA S119A C-terminal tryptic fragment
1JHF	LEXA G85D MUTANT
1JHH	LEXA S119A MUTANT

Derived Data

• SCOP Classification v1.75 - (2 Domains)
• CATH Classification v3.3.0 - (2 Domains)
• PFAM Classification - (2 Domains)
• GO Terms - (10 Terms)

Source : RCSB PDB
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